Home » Public Forums » GMCnet » Re: [GMCnet] bad master
| Re: [GMCnet] bad master [message #69670] |
Tue, 05 January 2010 03:37  |
James Moore
Messages: 71
Registered: January 2004
Karma: 0
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Member |
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Ken,
According to the Autozone website, the M1584 master cylinder is a
remanufactured MC with a 1 5/16" bore.
The M1730 is a remanufactured MC with a 1 1/4" bore.
Both have a 1/2" - 20 primary connection and a 9/16" - 18 secondary
connection.
Just right click on the pictures to display the details.
Now you know.
Jim Moore
75 PB with lousy brakes
Battle Ground, WA
Now you know the
> [Original Message]
> From: Ken Henderson <ken0henderson@gmail.com>
> To: gmclist <gmclist@temp.gmcnet.org>
> Date: 1/4/2010 8:33:38 PM
> Subject: Re: [GMCnet] bad master
>
> THAT's what I was hoping you'd tell me. :-)
>
> To me, one of the most frustrating data deficiencies related to the GMC is
> the almost total absence of generally available specifications for brake
> components. Why should we have to guess, or measure for ourselves the
bore,
> stroke, mounting dimensions, length, etc., etc. for all these things? But
> we do.
>
> As a WAG, which you could do better than I, based on experience, I'd guess
> that the 1584, and the other cylinders on the 10,000# truck, have larger
> bores, all around. Which would make the 1584 LESS suitable for a
> standard-braked GMC.
>
> I'd sure like to KNOW for a change.
>
> Ken H.
>
>
> On Mon, Jan 4, 2010 at 11:18 PM, Bob de Kruyff <NEXT2POOL@aol.com> wrote:
>
> >
> >
> > ""I hope this doesn't sound like quibbling, but I wanna know: Why did
you
> > (apparently from the cost) choose the M-1730 which is brake code JB7,
for
> > an
> > 8000# vehicle, instead of the M-1584, brake code JB8, for a 10,000#
> > vehicle?
> > Certainly not the $3.00 cheaper price. "Just 'cause that's what they
> > had..." is an acceptable answer since it worked. :-)""
> >
> > Now you do have my curiosity up--and mostly from the standpoint of
getting
> > on the same page--but what characteristics of the 1584 would make it a
> > better choice for our coaches than the 1730?
> >
> > --
> > Bob de Kruyff
> > 78 Eleganza
> > Chandler, AZ
> > _______________________________________________
> >
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] bad master [message #69671 is a reply to message #69670] |
Tue, 05 January 2010 04:30  |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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Has anyone explored the push-rod lengths on these different MCs ?
If you look at the data here, the push-rod changes with different MC.
http://gmcmotorhome.info/master%20cyl.html
gene
On Tue, Jan 5, 2010 at 1:37 AM, James Moore <j.moore.jr@mindspring.com>wrote:
> Ken,
> According to the Autozone website, the M1584 master cylinder is a
> remanufactured MC with a 1 5/16" bore.
>
> The M1730 is a remanufactured MC with a 1 1/4" bore.
>
> Both have a 1/2" - 20 primary connection and a 9/16" - 18 secondary
> connection.
>
> Just right click on the pictures to display the details.
>
> Now you know.
>
> Jim Moore
> 75 PB with lousy brakes
> Battle Ground, WA
>
> Now you know the
> > [Original Message]
> > From: Ken Henderson <ken0henderson@gmail.com>
> > To: gmclist <gmclist@temp.gmcnet.org>
> > Date: 1/4/2010 8:33:38 PM
> > Subject: Re: [GMCnet] bad master
> >
> > THAT's what I was hoping you'd tell me. :-)
> >
> > To me, one of the most frustrating data deficiencies related to the GMC
> is
> > the almost total absence of generally available specifications for brake
> > components. Why should we have to guess, or measure for ourselves the
> bore,
> > stroke, mounting dimensions, length, etc., etc. for all these things?
> But
> > we do.
> >
> > As a WAG, which you could do better than I, based on experience, I'd
> guess
> > that the 1584, and the other cylinders on the 10,000# truck, have larger
> > bores, all around. Which would make the 1584 LESS suitable for a
> > standard-braked GMC.
> >
> > I'd sure like to KNOW for a change.
> >
> > Ken H.
> >
> >
> > On Mon, Jan 4, 2010 at 11:18 PM, Bob de Kruyff <NEXT2POOL@aol.com>
> wrote:
> >
> > >
> > >
> > > ""I hope this doesn't sound like quibbling, but I wanna know: Why did
> you
> > > (apparently from the cost) choose the M-1730 which is brake code JB7,
> for
> > > an
> > > 8000# vehicle, instead of the M-1584, brake code JB8, for a 10,000#
> > > vehicle?
> > > Certainly not the $3.00 cheaper price. "Just 'cause that's what they
> > > had..." is an acceptable answer since it worked. :-)""
> > >
> > > Now you do have my curiosity up--and mostly from the standpoint of
> getting
> > > on the same page--but what characteristics of the 1584 would make it a
> > > better choice for our coaches than the 1730?
> > >
> > > --
> > > Bob de Kruyff
> > > 78 Eleganza
> > > Chandler, AZ
> > > _______________________________________________
> > >
> > _______________________________________________
> > GMCnet mailing list
> > List Information and Subscription Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] bad master [message #69673 is a reply to message #69670] |
Tue, 05 January 2010 06:48 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
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Senior Member |
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Bob, looks like Jim found the answer we were looking for, in this case. And
that confirms our hypothesis. I hope Gene will capture this tiny bit of
information in his MC table.
I really hope anyone planning to change their brakes will study and
understand Dave Mumert's brake calculations:
http://gmcmotorhome.info/GMCBrakeCalcs.pdf
<http://gmcmotorhome.info/GMCBrakeCalcs.pdf>In this case, the 1-5/16 MC is
not included, but that's just a little smaller bore than 34mm, so we can use
the 34mm numbers to compare: The 1730 will produce about 15% more pressure
for a given pedal force than the 1584 would have. And if you could have
found a 1-1/8" bore, it would have produced about 25% more than the 1730!
So smaller is better -- as long as there's enough volume to supply the
need.
Ken H.
On Tue, Jan 5, 2010 at 4:37 AM, James Moore <j.moore.jr@mindspring.com>wrote:
> Ken,
> According to the Autozone website, the M1584 master cylinder is a
> remanufactured MC with a 1 5/16" bore.
>
> The M1730 is a remanufactured MC with a 1 1/4" bore.
>
> Both have a 1/2" - 20 primary connection and a 9/16" - 18 secondary
> connection.
>
> Just right click on the pictures to display the details.
>
> Now you know.
>
> Jim Moore
> 75 PB with lousy brakes
> Battle Ground, WA
>
> Now you know the
> > [Original Message]
> > From: Ken Henderson <ken0henderson@gmail.com>
> > To: gmclist <gmclist@temp.gmcnet.org>
> > Date: 1/4/2010 8:33:38 PM
> > Subject: Re: [GMCnet] bad master
> >
> > THAT's what I was hoping you'd tell me. :-)
> >
> > To me, one of the most frustrating data deficiencies related to the GMC
> is
> > the almost total absence of generally available specifications for brake
> > components. Why should we have to guess, or measure for ourselves the
> bore,
> > stroke, mounting dimensions, length, etc., etc. for all these things?
> But
> > we do.
> >
> > As a WAG, which you could do better than I, based on experience, I'd
> guess
> > that the 1584, and the other cylinders on the 10,000# truck, have larger
> > bores, all around. Which would make the 1584 LESS suitable for a
> > standard-braked GMC.
> >
> > I'd sure like to KNOW for a change.
> >
> > Ken H.
> >
> >
> > On Mon, Jan 4, 2010 at 11:18 PM, Bob de Kruyff <NEXT2POOL@aol.com>
> wrote:
> >
> > >
> > >
> > > ""I hope this doesn't sound like quibbling, but I wanna know: Why did
> you
> > > (apparently from the cost) choose the M-1730 which is brake code JB7,
> for
> > > an
> > > 8000# vehicle, instead of the M-1584, brake code JB8, for a 10,000#
> > > vehicle?
> > > Certainly not the $3.00 cheaper price. "Just 'cause that's what they
> > > had..." is an acceptable answer since it worked. :-)""
> > >
> > > Now you do have my curiosity up--and mostly from the standpoint of
> getting
> > > on the same page--but what characteristics of the 1584 would make it a
> > > better choice for our coaches than the 1730?
> > >
> > > --
> > > Bob de Kruyff
> > > 78 Eleganza
> > > Chandler, AZ
> > > _______________________________________________
> > >
> > _______________________________________________
> > GMCnet mailing list
> > List Information and Subscription Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] bad master [message #69679 is a reply to message #69673] |
Tue, 05 January 2010 09:25 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
""Bob, looks like Jim found the answer we were looking for, in this case. And
that confirms our hypothesis. I hope Gene will capture this tiny bit of
information in his MC table.
I really hope anyone planning to change their brakes will study and
understand Dave Mumert's brake calculations:
http://gmcmotorhome.info/GMCBrakeCalcs.pdf
<http://gmcmotorhome.info/GMCBrakeCalcs.pdf>In this case, the 1-5/16 MC is
not included, but that's just a little smaller bore than 34mm, so we can use
the 34mm numbers to compare: The 1730 will produce about 15% more pressure
for a given pedal force than the 1584 would have. And if you could have
found a 1-1/8" bore, it would have produced about 25% more than the 1730!
So smaller is better -- as long as there's enough volume to supply the
need.""
Yes--I was looking at the Autozone page and noticed the M/C specs on there. As you say, more pressure is what we want if we have enough volume. So, it seems if we keep the rears adjusted, the 1730 would be a decent choice. There will be some pedal travel tradeoff, and some people may not like that. I'm not sure if we'll ever totally answer this question, but I'm comfortable that with my stock coach, I'd prefer the 1730.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] bad master [message #69684 is a reply to message #69679] |
Tue, 05 January 2010 13:52 |
Terry Skinner
Messages: 379
Registered: January 2004
Karma: 0
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Senior Member |
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Seems to me that at a price of $16 you could test the difference,
maybe??.........Terry
On Tue, Jan 5, 2010 at 7:25 AM, Bob de Kruyff <NEXT2POOL@aol.com> wrote:
>
>
> ""Bob, looks like Jim found the answer we were looking for, in this case. And
> that confirms our hypothesis. I hope Gene will capture this tiny bit of
> information in his MC table.
>
> I really hope anyone planning to change their brakes will study and
> understand Dave Mumert's brake calculations:
> http://gmcmotorhome.info/GMCBrakeCalcs.pdf
>
> <http://gmcmotorhome.info/GMCBrakeCalcs.pdf>In this case, the 1-5/16 MC is
> not included, but that's just a little smaller bore than 34mm, so we can use
> the 34mm numbers to compare: The 1730 will produce about 15% more pressure
> for a given pedal force than the 1584 would have. And if you could have
> found a 1-1/8" bore, it would have produced about 25% more than the 1730!
> So smaller is better -- as long as there's enough volume to supply the
> need.""
>
> Yes--I was looking at the Autozone page and noticed the M/C specs on there. As you say, more pressure is what we want if we have enough volume. So, it seems if we keep the rears adjusted, the 1730 would be a decent choice. There will be some pedal travel tradeoff, and some people may not like that. I'm not sure if we'll ever totally answer this question, but I'm comfortable that with my stock coach, I'd prefer the 1730.
>
>
>
>
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
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| Re: [GMCnet] bad master [message #69694 is a reply to message #69684] |
Tue, 05 January 2010 15:53 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
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""Seems to me that at a price of $16 you could test the difference,
maybe??.........Terry""
Yah--but the lack of time!! I think Ken H is the perfect brake tester here!! Did you notice how he dangled the worm out there--he's trapped a few of us before!
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] bad master [message #69724 is a reply to message #69694] |
Tue, 05 January 2010 20:00 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
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""Yah--but the lack of time!! I think Ken H is the perfect brake tester here!! Did you notice how he dangled the worm out there--he's trapped a few of us before! ""
Ken--you are very quiet all of a sudden 
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] bad master [message #69732 is a reply to message #69729] |
Tue, 05 January 2010 21:17 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""I can't -- I've got discs all around, including 80mm fronts. A 1-1/8"
doesn't displace enough to leave me an adequate safety margin. I had a 34
mm MC and replaced it with a 1-1/4" for just this reason -- more line
pressure. What I didn't do is run any calibrated tests; I just know I don't
have to push quite as hard -- and have less free pedal.""
Ah Ah Ah--Ken, it's not going to be that easy. We all depend on you for totally un-biased data. Lord knows I'll never be that person:) Besides, you are retired and we all worry that your brain may not be getting enough stimulation.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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